A NERS-SERS substrate microfluidic photon material fingerprint target

Abstract

The present invention provides a NERS-SERS substrate microfluidic photon material fingerprint target. Its structure includes a microfluidic unit and a temperature gradient controller; the temperature gradient controller includes two micro temperature sensors, a semiconductor cooling plate and a micro heating plate; the microfluidic unit includes a metal nanoparticle sol storage, a recycler and a four-stage microfluidic channel. A gap enhanced Raman scattering combined with surface enhanced Raman scattering (NERS-SERS) substrate is provided in the third-stage microfluidic channel, and the NERS-SERS substrate is composed of a sinusoidal silver grating and a metal nanoparticle sol; the semiconductor cooling plate and the micro heating plate are arranged to ensure that a temperature gradient is generated at both ends of the microfluidic unit. The present invention has the advantages of lightness, high integration, high sensitivity, continuous detection, good environmental protection, etc., and is particularly suitable for portable and repeatable identification of the types, varieties and "Raman fingerprints" of explosives such as trace ammunition in the air.

Description

Technical Field

[0001] The invention relates to the technical fields of photon surface enhanced Raman scattering (SERS) spectrum detection, microfluidic material detection and trace explosive detection, and in particular to a NERS-SERS substrate microfluidic photon material fingerprint target. Background Art

[0002] In the current surface enhanced Raman scattering (SERS) microfluidic detection technology, there are two main types of Raman enhancement substrates widely used: one is a single metal nanoparticle sol, including gold nanoparticle sol and silver nanoparticle sol; the other is a nanoarray structure, including a hemispherical nanoarray structure, a columnar nanoarray structure, etc. The SERS enhancement factor of a single metal nanoparticle sol can generally reach 10 8 In order to improve the detection sensitivity, the SERS enhancement factor needs to be improved. The Raman enhancement substrate with nano-array structure has the defect of not being able to achieve continuous detection. The reason is that the detection molecules are easily adsorbed on the nano-array structure. After one detection, the substrate needs to be cleaned to remove the adsorbed detection molecules to avoid affecting the next detection result. Summary of the invention

[0003] The purpose of the present invention is to provide a NERS-SERS substrate microfluidic photon material fingerprint target to solve the problems of the existing microfluidic SERS detection that cannot perform continuous sampling and detection and has low detection sensitivity.

[0004] The object of the present invention is achieved as follows: A NERS-SERS substrate microfluidic photon material fingerprint target comprises a microfluidic unit and a temperature gradient controller for controlling the temperature gradient at both ends of the microfluidic unit;

[0005] The microfluidic channel unit comprises a metal nanoparticle sol storage device, a first-level microfluidic channel, a second-level microfluidic channel, a third-level microfluidic channel, a fourth-level microfluidic channel and a metal nanoparticle sol recovery device; the metal nanoparticle sol storage device is used to store metal nanoparticle sol, and the metal nanoparticle sol recovery device is used to recover the metal nanoparticle sol; the first-level microfluidic channel, the second-level microfluidic channel, the third-level microfluidic channel and the fourth-level microfluidic channel are connected in sequence, and the metal nanoparticle sol in the metal nanoparticle sol storage device can enter the metal nanoparticle sol recovery device after passing through the first-level microfluidic channel, the second-level microfluidic channel, the third-level microfluidic channel and the fourth-level microfluidic channel in sequence; the upper surface of the metal nanoparticle sol recovery device is an open structure;

[0006] The second-stage microfluidic channel includes at least three capillary microfluidic channels, and the upper surface of each capillary microfluidic channel is a completely open structure; the second-stage microfluidic channel is used to allow the metal nanoparticle sol in the microfluidic channel unit to absorb the trace substances to be detected in the concentrated air;

[0007] The third-stage microfluidic channel is a microfluidic channel integrated with a SERS enhanced detection area; a laser incident and detection signal collection hole is arranged on the upper surface of the third-stage microfluidic channel; a periodic sinusoidal silver grating is integrated on the lower surface of the third-stage microfluidic channel, and the sinusoidal silver grating and the metal nanoparticle sol flowing thereon together constitute a NERS-SERS substrate;

[0008] The temperature gradient controller includes a first micro temperature sensor, a second micro temperature sensor, a micro heating plate and a semiconductor cooling plate;

[0009] The first micro temperature sensor is located below the metal nanoparticle sol recovery device and is used to detect the temperature around the metal nanoparticle sol recovery device; the second micro temperature sensor is located below the metal nanoparticle sol storage device and is used to detect the temperature around the metal nanoparticle sol storage device;

[0010] The micro-heating plate is located below the first micro-temperature sensor and is used to increase the temperature around the metal nanoparticle sol recovery device; the semiconductor cooling plate is located below the second micro-temperature sensor and is used to reduce the temperature around the metal nanoparticle sol storage device.

[0011] The sinusoidal silver grating is processed by laser interference lithography and physical vapor deposition technology. The period of the sinusoidal silver grating is 400nm-1000nm, the sinusoidal amplitude is 10nm-100nm, and the thickness of the grating silver layer is 50nm-200nm.

[0012] The metal nanoparticle sol flowing in the microfluidic channel unit is spherical in shape, and the diameter of the spherical particles is 50nm to 200nm.

[0013] The metal nanoparticle sol storage device and the metal nanoparticle sol recovery device are both rectangular container structures; the metal nanoparticle sol storage device has a length of 1000μm to 5000μm, a width of 1000μm to 5000μm, and a depth of 50μm to 200μm; the metal nanoparticle sol recovery device has a length of 1000μm to 5000μm, a width of 1000μm to 5000μm, and a depth of 50μm to 200μm.

[0014] The first-level microfluidic channel and the fourth-level microfluidic channel are both long strip channel structures with rectangular or circular cross-sections; the length of the first-level microfluidic channel is 1 mm to 5 mm, the width is 100 μm to 500 μm, and the depth is 50 μm to 200 μm; the length of the fourth-level microfluidic channel is 1 mm to 5 mm, the width is 100 μm to 500 μm, and the depth is 50 μm to 200 μm.

[0015] Each capillary microchannel in the second-stage microchannel has a width of 10 μm to 30 μm, a length of 1 mm to 5 mm, and a depth of 5 μm to 20 μm.

[0016] The third-level microfluidic channel is a long strip channel structure; the length of the third-level microfluidic channel is 0.2 mm to 2 mm, the width is 100 μm to 500 μm, and the depth is 5 μm to 20 μm.

[0017] The first micro temperature sensor is 2 mm to 5 mm away from the bottom of the metal nano particle sol recovery device; the micro heating plate is 5 mm to 15 mm away from the bottom of the metal nano particle sol recovery device.

[0018] The second micro temperature sensor is 2 mm to 5 mm away from the bottom of the metal nanoparticle sol storage device; the semiconductor refrigeration sheet is 5 mm to 15 mm away from the bottom of the metal nanoparticle sol storage device.

[0019] The microfluidic unit in the present invention is a bionic canine nasal cavity internal structure. The present invention can continuously detect whether the air contains trace amounts of explosives such as ammunition, and has high detection sensitivity. By controlling the temperature gradient at both ends of the microfluidic unit, the flow rate of the metal nanoparticle sol in the microfluidic unit is adjusted to ensure that the dimer in the microfluidic unit of the third-level integrated SERS enhanced detection area has a high concentration, thereby realizing the role of the NERS-SERS substrate and further improving the sensitivity of SERS detection. By controlling the temperature gradient at both ends of the microfluidic unit, the bionic plant transpiration effect is used to realize the continuous renewal flow of the metal nanoparticle sol in the microfluidic unit, solving the problem that the current microfluidic SERS detection technology cannot continuously sample and quickly detect. Therefore, the present invention has the advantages of high integration, high sensitivity, and continuous sampling.

[0020] The periodic sinusoidal silver grating in the NERS-SERS substrate of the present invention is not easy to adsorb detection molecules, and can be detected again without cleaning. At the same time, the temperature gradient controller of the present invention controls the continuous flow of the metal nanoparticle sol in the microchannel unit, thereby achieving continuous detection. The present invention organically combines microfluidic technology with NERS-SERS detection technology, combines the characteristics and advantages of both, and realizes high-sensitivity, continuous online detection of trace explosive gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a NERS-SERS substrate microfluidic photon material fingerprint target in the present invention, wherein "1" or the dotted box represents the "microfluidic unit" in the present invention.

[0022] Figure 2 It is a schematic diagram of the structure of the second-stage microfluidic channel and the third-stage microfluidic channel of the microfluidic channel unit in the present invention.

[0023] Figure 3 It is a schematic diagram of the structure of the NERS-SERS substrate on the lower surface of the third-stage microchannel in the present invention.

[0024] Figure 4 This is a schematic diagram of the electromagnetic field intensity distribution between ordinary single gold nanoparticle sols.

[0025] Figure 5 It is a schematic diagram of the electromagnetic field intensity distribution between the gold nanoparticle sols in the NERS-SERS substrate of the present invention.

[0026] Figure 6 It is a schematic diagram of the concentration distribution of metal nanoparticle sol dimers in the four-stage microchannel of the present invention.

[0027] In the figure: 1. microfluidic unit, 2. metal nanoparticle sol storage device, 3. metal nanoparticle sol loading channel, 4. first-stage microfluidic channel, 5. second-stage microfluidic channel, 6. third-stage microfluidic channel, 7. laser incident and detection signal collection hole, 8. fourth-stage microfluidic channel, 9. metal nanoparticle sol recovery device, 10. first micro temperature sensor, 11. micro heating plate, 12. semiconductor cooling plate, 13. second micro temperature sensor, 14. NERS-SERS substrate, 15. sinusoidal silver grating, 16. metal nanoparticle sol. DETAILED DESCRIPTION

[0028] like Figure 1 As shown, the target of the present invention includes a microfluidic unit 1 and a temperature gradient controller. The microfluidic unit 1 includes a metal nanoparticle sol storage 2, a first-level microfluidic channel 4, a second-level microfluidic channel 5, a third-level microfluidic channel 6, a fourth-level microfluidic channel 8 and a metal nanoparticle sol recovery device 9. The temperature gradient controller includes a first micro temperature sensor 10, a second micro temperature sensor 13, a micro heating plate 11 and a semiconductor cooling plate 12.

[0029] The metal nanoparticle sol storage device 2 and the metal nanoparticle sol recovery device 9 are both rectangular container structures. The metal nanoparticle sol storage device 2 is a closed structure, and the upper surface of the metal nanoparticle sol recovery device 9 is a completely open structure, which is convenient for the generation of transpiration. The length of the metal nanoparticle sol storage device 2 is 1000μm to 5000μm, the width is 1000μm to 5000μm, and the depth is 50μm to 200μm. The length of the metal nanoparticle sol recovery device 9 is 1000μm to 5000μm, the width is 1000μm to 5000μm, and the depth is 50μm to 200μm.

[0030] A metal nanoparticle sol loading channel 3 is provided on the upper surface of the metal nanoparticle sol storage device 2. The metal nanoparticle sol loading channel 3 can be, for example, a vertical circular tube structure. The metal nanoparticle sol loading channel 3 is connected to the inner cavity of the metal nanoparticle sol storage device 2. The metal nanoparticle sol can be introduced into the metal nanoparticle sol storage device 2 through the metal nanoparticle sol loading channel 3.

[0031] The metal nanoparticle sol in the metal nanoparticle sol storage device 2 can enter the metal nanoparticle sol recovery device 9 after passing through the first-stage microfluidic channel 4, the second-stage microfluidic channel 5, the third-stage microfluidic channel 6 and the fourth-stage microfluidic channel 8 in sequence. The first-stage microfluidic channel 4 is connected to the metal nanoparticle sol storage device 2, and the fourth-stage microfluidic channel 8 is connected to the metal nanoparticle sol recovery device 9. The first-stage microfluidic channel 4 and the fourth-stage microfluidic channel 8 are long strip channel structures, and their cross-sections can be rectangular or circular. The length of the first-stage microfluidic channel 4 is 1 mm to 5 mm, the width is 100 μm to 500 μm, and the depth is 50 μm to 200 μm. The length of the fourth-stage microfluidic channel 8 is 1 mm to 5 mm, the width is 100 μm to 500 μm, and the depth is 50 μm to 200 μm.

[0032] like Figure 2 As shown, the second-stage microfluidic channel 5 is composed of at least three capillary microfluidic channels arranged in parallel, and the upper surface of each capillary microfluidic channel is a completely open structure, and the width of each capillary microfluidic channel is 10μm to 30μm, the length is 1 mm to 5mm, and the depth is 5μm to 20μm. The second-stage microfluidic channel 5 is used to allow the metal nanoparticle sol in the microfluidic channel unit 1 to absorb the trace substances to be detected in the concentrated air, so it is an open microfluidic channel.

[0033] The third-level microfluidic channel 6 is also a long strip channel structure. The third-level microfluidic channel 6 is a microfluidic channel integrated with a SERS enhanced detection zone. The length of the third-level microfluidic channel 6 is 0.2 mm to 2 mm, the width is 100 μm to 500 μm, and the depth is 5 μm to 20 μm. A laser incident and detection signal collection hole 7 is provided on the upper surface of the third-level microfluidic channel 6. The signal emitted by the laser can be irradiated into the third-level microfluidic channel 6 through the hole, and the Raman spectrometer can also detect the Raman signal generated by the NERS-SERS substrate 14 in the third-level microfluidic channel 6 through the hole. The matching laser operating wavelength of the SERS enhanced detection zone is 470nm, 532nm, 658nm or 785nm.

[0034] Combination Figure 3 , a periodic sinusoidal silver grating 15 is integrated on the lower surface of the third-level microfluidic channel 6. The sinusoidal silver grating 15 and the metal nanoparticle sol 16 flowing thereon constitute a NERS (Nanogap Enhanced Raman Scattering)-SERS substrate 14, which is a substrate combining gap enhanced Raman scattering and surface enhanced Raman scattering. The sinusoidal silver grating 15 is integrated into the lower surface of the third-level microfluidic channel 6 by laser interference lithography and physical vapor deposition process. The period of the sinusoidal silver grating 15 is 400 nm to 1000 nm, the sinusoidal amplitude is 10 nm to 100 nm, and the thickness of the silver grating film is 50 nm to 200 nm. The metal nanoparticle sol 16 flows in the entire microfluidic channel unit 1, which can be a silver or gold nanoparticle sol, and is used to adsorb trace molecules of substances to be detected in the air and form dimers. The metal nanoparticle sol 16 is spherical in shape, and the diameter of the spherical particles is 50 to 200 nm.

[0035] like Figure 6 As shown, Figure 6 It is a schematic diagram of the distribution of the metal nanoparticle sol dimer concentration in the four-level microfluidic channel. In the figure, the area with a small gray value represents a lower concentration, and the area with a large gray value represents a higher concentration. It can be seen that the concentration of the metal nanoparticle sol dimer gradually increases from the first microfluidic channel to the fourth microfluidic channel and has reached a higher concentration in the third microfluidic channel.

[0036] like Figure 4 and Figure 5 As shown, taking gold nanoparticle sol as an example, Figure 4 is the electromagnetic field intensity distribution between ordinary single gold nanoparticle sols, Figure 5 It is the electromagnetic field intensity distribution between the gold nanoparticle sols in the NERS-SERS substrate. Obviously, the electromagnetic field intensity of the latter is significantly improved than that of the former. Therefore, the detection sensitivity can be improved through the present invention.

[0037] The present invention adopts NERS-SERS substrate, that is, metal nanoparticle sol is combined with periodic sinusoidal silver grating, the surface plasmon resonance effect formed by the periodic sinusoidal silver grating and the local plasmon resonance effect formed by the metal nanoparticle sol can be coupled, so that the local electromagnetic field between the metal nanoparticle sol is further enhanced, and the SERS enhancement factor can reach 10 9 , which is an order of magnitude higher than the existing technology, thereby improving the sensitivity of SERS detection and achieving high-sensitivity detection.

[0038] The first micro temperature sensor 10 is located below the metal nanoparticle sol recovery device 9, and the first micro temperature sensor 10 is 2 mm to 5 mm away from the bottom of the metal nanoparticle sol recovery device 9. The micro heating plate 11 is located below the first micro temperature sensor 10, and the micro heating plate 11 is 5 mm to 15 mm away from the bottom of the metal nanoparticle sol recovery device 9. The size of the micro heating plate 11 is in the millimeter order, and the size of the micro heating plate 11 in this embodiment is 8×8×3.5 mm.

[0039] The second micro temperature sensor 13 is located below the metal nanoparticle sol storage device 2, and the second micro temperature sensor 13 is 2 mm to 5 mm away from the bottom of the metal nanoparticle sol storage device 2. The size of the micro temperature sensor is in the millimeter order. In this embodiment, the size of the first micro temperature sensor 10 and the second micro temperature sensor 13 are both 4×4×3 mm. The semiconductor cooling sheet 12 is located below the second micro temperature sensor 13, and the semiconductor cooling sheet 12 is 5 mm to 15 mm away from the bottom of the metal nanoparticle sol storage device 2.

[0040] The semiconductor cooling sheet 12 is used to reduce the temperature of the area around the metal nanoparticle sol storage 2, and the micro-heating sheet 11 is used to increase the temperature of the area around the metal nanoparticle sol recovery device 9. The first micro-temperature sensor 10 is used to measure the temperature of the area around the metal nanoparticle sol recovery device 9, and the second micro-temperature sensor 13 is used to measure the temperature of the area around the metal nanoparticle sol storage device 2, thereby controlling the temperature gradient at both ends of the microfluidic unit 1. The flow rate of the metal nanoparticle sol 16 in the microfluidic unit 1 is adjusted by transpiration, and the metal nanoparticle sol 16 flows from the metal nanoparticle sol storage device 2 to the metal nanoparticle sol recovery device 9.

[0041] The present invention provides a NERS-SERS substrate microfluidic photon material fingerprint target that can be combined with a Raman spectrometer and a laser to detect trace explosive molecules in the air. The NERS-SERS substrate microfluidic photon material fingerprint target includes a microchannel unit and a temperature gradient controller; the temperature gradient controller includes two micro temperature sensors, a semiconductor refrigeration sheet and a micro heating sheet; the microchannel unit includes a metal nanoparticle sol storage device, a recycler and a four-stage microchannel. A NERS-SERS substrate is provided in the third-stage microchannel, and the NERS-SERS substrate is composed of a periodic sinusoidal silver grating and a metal nanoparticle sol thereon; the semiconductor refrigeration sheet and the micro heating sheet are arranged to ensure that a temperature gradient is generated at both ends of the microchannel unit, and then the required temperature gradient is controlled by the detection result of the micro temperature sensor, thereby utilizing transpiration to drive the metal nanoparticle sol in the microchannel unit to continuously update and flow. The present invention has the advantages of being light, highly integrated, highly sensitive, capable of continuous detection, and environmentally friendly, and is particularly suitable for portable, repeatable identification of the types, varieties, and "Raman fingerprints" of explosives such as trace ammunition present in the air.

Claims

1. A NERS-SERS substrate microfluidic photon material fingerprint target, characterized in that: It includes a microfluidic unit and a temperature gradient controller for controlling the temperature gradient at both ends of the microfluidic unit; The microfluidic channel unit comprises a metal nanoparticle sol storage device, a first-level microfluidic channel, a second-level microfluidic channel, a third-level microfluidic channel, a fourth-level microfluidic channel and a metal nanoparticle sol recovery device; the metal nanoparticle sol storage device is used to store metal nanoparticle sol, and the metal nanoparticle sol recovery device is used to recover the metal nanoparticle sol; the first-level microfluidic channel, the second-level microfluidic channel, the third-level microfluidic channel and the fourth-level microfluidic channel are connected in sequence, and the metal nanoparticle sol in the metal nanoparticle sol storage device can enter the metal nanoparticle sol recovery device after passing through the first-level microfluidic channel, the second-level microfluidic channel, the third-level microfluidic channel and the fourth-level microfluidic channel in sequence; the upper surface of the metal nanoparticle sol recovery device is an open structure; The second-stage microfluidic channel includes at least three capillary microfluidic channels, and the upper surface of each capillary microfluidic channel is a completely open structure; the second-stage microfluidic channel is used to allow the metal nanoparticle sol in the microfluidic channel unit to absorb the trace substances to be detected in the concentrated air; The third-stage microfluidic channel is a microfluidic channel integrated with a SERS enhanced detection area; a laser incident and detection signal collection hole is arranged on the upper surface of the third-stage microfluidic channel; a periodic sinusoidal silver grating is integrated on the lower surface of the third-stage microfluidic channel, and the sinusoidal silver grating and the metal nanoparticle sol flowing thereon together constitute a NERS-SERS substrate; The temperature gradient controller includes a first micro temperature sensor, a second micro temperature sensor, a micro heating plate and a semiconductor cooling plate; The first micro temperature sensor is located below the metal nanoparticle sol recovery device and is used to detect the temperature around the metal nanoparticle sol recovery device; the second micro temperature sensor is located below the metal nanoparticle sol storage device and is used to detect the temperature around the metal nanoparticle sol storage device; The micro-heating sheet is located below the first micro-temperature sensor and is used to increase the temperature around the metal nanoparticle sol recovery device; the semiconductor cooling sheet is located below the second micro-temperature sensor and is used to reduce the temperature around the metal nanoparticle sol storage device; The sinusoidal silver grating is processed by laser interference lithography and physical vapor deposition technology; The period of the sinusoidal silver grating is 400nm-1000nm, the sinusoidal amplitude is 10nm-100nm, and the thickness of the grating silver layer is 50nm-200nm; The metal nanoparticle sol flowing in the microfluidic unit is spherical in shape, and the diameter of the spherical particles is 50nm to 200nm; The first-stage microfluidic channel and the fourth-stage microfluidic channel are both long strip channel structures, and their cross-sections are rectangular or circular; the length of the first-stage microfluidic channel is 1 mm to 5 mm, the width is 100 μm to 500 μm, and the depth is 50 μm to 200 μm; the length of the fourth-stage microfluidic channel is 1 mm to 5 mm, the width is 100 μm to 500 μm, and the depth is 50 μm to 200 μm; Each capillary microchannel in the second-stage microchannel has a width of 10 μm to 30 μm, a length of 1 mm to 5 mm, and a depth of 5 μm to 20 μm; The third-level microfluidic channel is a long strip channel structure; the length of the third-level microfluidic channel is 0.2 mm to 2 mm, the width is 100 μm to 500 μm, and the depth is 5 μm to 20 μm.

2. The NERS-SERS substrate microfluidic photon material fingerprint target according to claim 1, characterized in that: The metal nanoparticle sol storage device and the metal nanoparticle sol recovery device are both rectangular container structures; the metal nanoparticle sol storage device has a length of 1000μm to 5000μm, a width of 1000μm to 5000μm, and a depth of 50μm to 200μm; the metal nanoparticle sol recovery device has a length of 1000μm to 5000μm, a width of 1000μm to 5000μm, and a depth of 50μm to 200μm.

3. The NERS-SERS substrate microfluidic photon material fingerprint target according to claim 1, characterized in that: The first micro temperature sensor is 2 mm to 5 mm away from the bottom of the metal nano particle sol recovery device; the micro heating plate is 5 mm to 15 mm away from the bottom of the metal nano particle sol recovery device.

4. The NERS-SERS substrate microfluidic photon material fingerprint target according to claim 1, characterized in that: The second micro temperature sensor is 2 mm to 5 mm away from the bottom of the metal nanoparticle sol storage device; the semiconductor refrigeration sheet is 5 mm to 15 mm away from the bottom of the metal nanoparticle sol storage device.

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